// Copyright (C) Kumo inc. and its affiliates.
// Author: Jeff.li lijippy@163.com
// All rights reserved.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
//


#pragma once

namespace kumo::pollux {
    /// Used to temporarily set the value of a variable till it goes out of scope.
    template<typename T>
    class ScopedVarSetter {
    public:
        ScopedVarSetter(T *place, T value) : place_(place), old_(*place) {
            *place = value;
        }

        // Updates "place" to "value" if condition is true. No-op otherwise.
        ScopedVarSetter(T *place, T value, bool condition)
            : place_(place), old_(*place) {
            if (condition) {
                *place = value;
            }
        }

        ~ScopedVarSetter() {
            *place_ = old_;
        }

    private:
        T *place_;
        T old_;
    };
} // namespace kumo::pollux
